Deployment简介
Deployment 为 Pod 和 ReplicaSet 提供了一个声明式定义 (declarative) 方法，用来替代以前的ReplicationController 来方便的管理应用。典型的应用场景包括；定义 Deployment 来创建 Pod 和 ReplicaSet
- 滚动升级和回滚应用
- 扩容和缩容
- 暂停和继续 Deploymen
Deployment 无状态服务最常用的Pod管理器
Deployment 实际是管理ReplicaSet Deployment默认会保存10个ReplicaSet历史版本
Deployment 会把ReplicaSet之前个版本的副本数修改为0
Deployment 字段格式
apiVersion: apps/v1 #API群组及版本
kind: Deployment #资源类型特有标识
metadata:
name #资源名称,在作用域中要唯一
namespace #名称空间;Deployment隶属名称空间级别
spec:
minReadySeconds #Pod就绪后多少秒内任一容器无crash方可视为“就绪”
replicas #期望的Pod副本数,默认为1
selector 示例1: 创建Deployment控制器 Pod副本数为4
[root@k8s-master PodControl]# cat deployment-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: deployment-demo
spec:
replicas: 4 #副本数来4
selector:
matchLabels:
app: demoapp
release: stable
template:
metadata:
labels :
app: demoapp
release: stable
spec:
containers:
- name: demoapp
image: ikubernetes/demoapp:${VERSION}
ports:
- containerPort: 80
name: http
[root@k8s-master PodControl]# kubectl apply -f deployment-demo.yaml
deployment.apps/deployment-demo created
[root@k8s-master PodControl]# VERSION=v1.0 envsubst < deployment-demo.yaml |kubectl apply -f -
deployment.apps/deployment-demo created
[root@k8s-master PodControl]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
deployment-demo 4/4 4 4 54s
#可以看到创建了同名的rs deployment实际管理的是rs而不是Pod
#名称中的 fb544c5d8 是通过配置文的生成的hash值,当检查到配置文件hash值变化就会启到更新
[root@k8s-master PodControl]# kubectl get rs
NAME DESIRED CURRENT READY AGE
deployment-demo-fb544c5d8 4 4 4 56s
[root@k8s-master PodControl]# kubectl get pod
NAME READY STATUS RESTARTS AGE
deployment-demo-fb544c5d8-kz8fn 1/1 Running 0 58s
deployment-demo-fb544c5d8-p6q4v 1/1 Running 0 58s
deployment-demo-fb544c5d8-ttjmt 1/1 Running 0 58s
deployment-demo-fb544c5d8-x2lqw 1/1 Running 0 58s
[root@k8s-master PodControl]# kubectl describe deployment/deployment-demo
Name: deployment-demo
Namespace: default
CreationTimestamp: Mon, 16 Aug 2021 16:17:28 +0800
Labels:
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=demoapp,release=stable
Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType: RollingUpdate #可以看到默认的更新策略
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge #默认的更新比例为 25%
更新deployment rollout命令查看状态
[root@k8s-master PodControl]# kubectl rollout --help #查看张帮助选项
Manage the rollout of a resource.
Valid resource types include: #可以更新的资源类型
* deployments
* daemonsets
* statefulsets
Examples:
# Rollback to the previous deployment
kubectl rollout undo deployment/abc
# Check the rollout status of a daemonset
kubectl rollout status daemonset/foo
Available Commands:
history View rollout history #历史记录
pause Mark the provided resource as paused #暂停
restart Restart a resource #重启
resume Resume a paused resource #恢复暂时资源
status Show the status of the rollout #查看资源更新状态
undo Undo a previous rollout #版本回退
[root@k8s-master PodControl]# VERSION=v1.1 envsubst < deployment-demo.yaml |kubectl apply -f -
deployment.apps/deployment-demo configured
[root@k8s-master PodControl]# kubectl rollout status deployment/deployment-demo
deployment "deployment-demo" successfully rolled out #查看更新状态成功
[root@k8s-master PodControl]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
deployment-demo 4/4 4 4 2
[root@k8s-master PodControl]# kubectl get rs
NAME DESIRED CURRENT READY AGE
deployment-demo-867c7d9d55 4 4 4 6m5s
deployment-demo-fb544c5d8 0 0 0 25m #旧版本副本数为0
[root@k8s-master PodControl]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deployment-demo-867c7d9d55-d6xvt 1/1 Running 0 6m55s 10.244.1.229 k8s-node1
deployment-demo-867c7d9d55-l65z9 1/1 Running 0 6m47s 10.244.2.209 k8s-node2
deployment-demo-867c7d9d55-vhs6t 1/1 Running 0 6m55s 10.244.3.56 k8s-node3
deployment-demo-867c7d9d55-zc8dm 1/1 Running 0 6m43s 10.244.1.230 k8s-node1
[root@k8s-master PodControl]# curl 10.244.1.229
iKubernetes demoapp v1.1 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-867c7d9d55-d6xvt, ServerIP: 10.244.1.229! 在次更新使用 kubectl rollout status查看更新状态状
[root@k8s-master PodControl]# VERSION=v1.2 envsubst < deployment-demo.yaml |kubectl apply -f - && kubectl rollout status deployment/deployment-demo deployment.apps/deployment-demo configured Waiting for deployment spec update to be observed... Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated... Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination... Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination... Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination... Waiting for deployment "deployment-demo" rollout to finish: 3 of 4 updated replicas are available... deployment "deployment-demo" successfully rolled out [root@k8s-master PodControl]# kubectl get rs #可以看到rs又多了一个版本副本数为0 NAME DESIRED CURRENT READY AGE deployment-demo-77d46c4794 4 4 4 2m25s deployment-demo-867c7d9d55 0 0 0 10m deployment-demo-fb544c5d8 0 0 0 29m #验证 [root@k8s-master PodControl]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES deployment-demo-77d46c4794-fbt5l 1/1 Running 0 2m44s 10.244.2.210 k8s-node2deployment-demo-77d46c4794-kdvn2 1/1 Running 0 3m20s 10.244.1.231 k8s-node1 deployment-demo-77d46c4794-lcm28 1/1 Running 0 3m20s 10.244.3.57 k8s-node3 deployment-demo-77d46c4794-x52sh 1/1 Running 0 2m40s 10.244.1.232 k8s-node1 [root@k8s-master PodControl]# curl 10.244.2.210 iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fbt5l, ServerIP: 10.244.2.210! 示例2: Deployment版本回滚
- 回滚 回滚时可以指定回滚版本,默认回滚到前一个版本,
- 这里需要注意的是,假设当前版本为A,前一个版本为B,回滚后当前版本A变成前一版本,再次回滚后A从前一版本回滚到最新版本,所以如果不指定版本,回滚只在最后两个版本间滚动
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo
REVISION CHANGE-CAUSE
1 #更新过3次 3个不同的版本 回滚时可以
2
3
[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo
deployment.apps/deployment-demo rolled back
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo
REVISION CHANGE-CAUSE
1
3
4 #版本2变成4为最新版本 序列号只会递增
[root@k8s-master PodControl]# kubectl rollout undo --dry-run=server deployment/deployment-demo #不执行测试是否能成功
deployment.apps/deployment-demo rolled back (server dry run)
[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo --to-revision=1 #回滚到指定版本
deployment.apps/deployment-demo rolled back
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo
REVISION CHANGE-CAUSE
3
4
5
[root@k8s-master PodControl]# kubectl get rs
NAME DESIRED CURRENT READY AGE
deployment-demo-77d46c4794 0 0 0 17m
deployment-demo-867c7d9d55 0 0 0 26m
deployment-demo-fb544c5d8 4 4 4 45m #只有最开始的rs副本数为4 其它都为0
[root@k8s-master PodControl]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deployment-demo-867c7d9d55-b65cm 0/1 Terminating 0 4m2s 10.244.1.234 k8s-node1
deployment-demo-867c7d9d55-pv8fp 1/1 Terminating 0 4m10s 10.244.3.58 k8s-node3
deployment-demo-867c7d9d55-tnhsg 1/1 Terminating 0 4m14s 10.244.1.233 k8s-node1
deployment-demo-867c7d9d55-wcvl7 1/1 Terminating 0 4m14s 10.244.2.211 k8s-node2
deployment-demo-fb544c5d8-5f9lp 1/1 Running 0 32s 10.244.1.235 k8s-node1
deployment-demo-fb544c5d8-d5lr9 1/1 Running 0 22s 10.244.1.236 k8s-node1
deployment-demo-fb544c5d8-lj5gt 1/1 Running 0 29s 10.244.3.59 k8s-node3
deployment-demo-fb544c5d8-t9swj 1/1 Running 0 32s 10.244.2.212 k8s-node2
[root@k8s-master PodControl]# curl 10.244.2.212 #测试回滚版本
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!
示例3: 使用 pause 模拟金丝雀发布
#指定回滚版本或更新版本后,马上暂停,这样只回滚或更新第一批Pod,模拟金丝雀发布让 用一小部分流量测试服务是否正常
[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo --to-revision=3 && kubectl rollout pause deployment/deployment-demo
deployment.apps/deployment-demo rolled back
deployment.apps/deployment-demo paused
#只更新了第一批就阻塞住了
[root@k8s-master PodControl]# kubectl rollout status deployment/deployment-demo
Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated...
[root@k8s-master PodControl]# kubectl get rs
NAME DESIRED CURRENT READY AGE
deployment-demo-58c8475bcc 0 0 0 5m42s
deployment-demo-77d46c4794 2 2 1 36m
deployment-demo-867c7d9d55 0 0 0 44m
deployment-demo-fb544c5d8 3 3 3 63m
[root@k8s-master ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demoapp-deploy ClusterIP 10.107.174.169 80/TCP 18s
#让流量
[root@k8s-master ~]# while true; do curl --connect-timeout 1 10.107.174.169; sleep .2;done #新旧版本同时存在
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fhz4l, ServerIP: 10.244.1.238!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-lj5gt, ServerIP: 10.244.3.59!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-5f9lp, ServerIP: 10.244.1.235!
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-kmrhn, ServerIP: 10.244.3.60!
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fhz4l, ServerIP: 10.244.1.238!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-lj5gt, ServerIP: 10.244.3.59!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-5f9lp, ServerIP: 10.244.1.235!
示例4: 修改Deployment滚动更新策略
- 更新策略需要根据自己的实际情况配置 比如流量较大,要保证一定的Pod数量,那就要保证更新时Pod的数量不能少
- 如果系统资源比较紧张,那更新时Pod的数量要保持不变,以免增大对系统资源的负担
[root@k8s-master PodControl]# cat deployment-demo-with-strategy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: deployment-demo-with-strategy
spec:
replicas: 4
selector:
matchLabels:
app: demoapp
release: stable
strategy: ture
template:
metadata:
labels :
app: demoapp
release: stable
strategy: ture
spec:
containers:
- name: demoapp
image: ikubernetes/demoapp:${VERSION}
ports:
- containerPort: 80
name: http
strategy:
type: RollingUpdate
rollingUpdate:
maxSurge: 0 #总的Pod数量不能多
maxUnavailable: 1 #总的数量可以减少1个 先减在加 在系统资源紧缺的时候使用
[root@k8s-master PodControl]# VERSION=v1.0 envsubst < deployment-demo-with-strategy.yaml |kubectl apply -f -
deployment.apps/deployment-demo-with-strategy created
[root@k8s-master PodControl]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
deployment-demo 5/4 2 5 90m
deployment-demo-with-strategy 4/4 4 4 49s
[root@k8s-master PodControl]# kubectl describe deployment/deployment-demo-with-strategy
Name: deployment-demo-with-strategy
Namespace: default
CreationTimestamp: Mon, 16 Aug 2021 17:46:52 +0800
Labels:
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=demoapp,release=stable,strategy=ture
Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 1 max unavailable, 0 max surge #更新策略生效
[root@k8s-master PodControl]# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
deployment-demo 5/4 2 5 93m
deployment-demo-with-strategy 4/4 4 4 3m58s
[root@k8s-master PodControl]# kubectl get pod
NAME READY STATUS RESTARTS AGE
deployment-demo-77d46c4794-fhz4l 1/1 Running 0 26m
deployment-demo-77d46c4794-kmrhn 1/1 Running 0 26m
deployment-demo-fb544c5d8-5f9lp 1/1 Running 0 46m
deployment-demo-fb544c5d8-lj5gt 1/1 Running 0 46m
deployment-demo-fb544c5d8-t9swj 1/1 Running 0 46m
deployment-demo-with-strategy-57b96bdc87-8mjzw 1/1 Running 0 39s
deployment-demo-with-strategy-57b96bdc87-k6rxx 1/1 Running 0 38s
deployment-demo-with-strategy-57b96bdc87-v4tdj 1/1 Running 0 38s
deployment-demo-with-strategy-57b96bdc87-zdvcp 1/1 Running 0 38s
#查看更新状态 先减后增
[root@k8s-master PodControl]# VERSION=v1.1 envsubst < deployment-demo-with-strategy.yaml |kubectl apply -f - && kubectl rollout status deployment/deployment-demo-with-strategy
deployment.apps/deployment-demo-with-strategy configured
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 0 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 0 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 of 4 updated replicas are available...
deployment "deployment-demo-with-strategy" successfully rolled out